Fix compile error
Fix compile error

niboshi/chainer,chainer/chainer,hvy/chainer,chainer/chainer,chainer/chainer,wkentaro/chainer,niboshi/chainer,chainer/chainer,wkentaro/chainer,niboshi/chainer,niboshi/chainer,hvy/chainer,wkentaro/chainer,hvy/chainer,hvy/chainer,wkentaro/chainer,pfnet/chainer